Heathrow and Gatwick among airports hit by air traffic control problems

Hundreds of flights into and out of the UK were thrown into chaos following a significant technical problem that crippled the systems of Nats, the nation’s air traffic control provider. The unprecedented disruption, which struck earlier on Tuesday, led to widespread cancellations and delays across the country, affecting tens of thousands of passengers and leaving airports struggling to manage the fallout.

The scale of the disruption quickly became apparent, with tracking website FlightRadar24 reporting at least 625 flights in or out of the UK had been cancelled by Tuesday evening. Major airlines bore the brunt of the crisis, with easyJet announcing over 200 cancellations and British Airways, the UK’s flag carrier, forced to scrap more than 100 services. While initial estimates suggested approximately 4% of UK flights were affected, the cascading nature of air travel disruption meant the true impact was far more extensive, with thousands more experiencing significant delays and diversions.

Nats, the National Air Traffic Services, is responsible for managing all air traffic over the UK and a large part of the North Atlantic. Its sophisticated flight processing system is the backbone of its operations, continually updating flight information as aircraft traverse UK airspace. This system is crucial for air traffic controllers to maintain a safe and orderly flow of traffic, processing flight plans and other operational data that dictate aircraft movements. When this vital system failed, the immediate consequence was a drastic reduction in Nats’ ability to safely manage the volume of air traffic.

The technical glitch effectively brought large swathes of UK airspace to a standstill. With the flight processing system compromised, air traffic controllers were severely limited in their capacity to approve new flight plans or guide existing flights. This led to a "ground stop" for departures, particularly from the busiest hubs, as a safety measure. Aircraft were prevented from taking off, creating immediate backlogs on airport aprons and runways.

Heathrow, one of Europe’s busiest airports and a critical global hub, was particularly hard hit. Departures were initially paused around lunchtime on Tuesday, causing significant queues and frustrated passengers. While traffic briefly resumed, it faced further, more severe disruption in the afternoon as the situation deteriorated. The airport, designed for a constant flow of arrivals and departures, quickly ran out of physical space for incoming flights because planes were not departing. This forced controllers to restrict landings, leading to a domino effect across Europe as flights bound for Heathrow were prevented from taking off from their origins. In a stark illustration of the crisis, thirteen Heathrow-bound flights were diverted to other airports, not just elsewhere in the UK, but also across Europe, leaving passengers stranded far from their intended destinations.

The ripple effect extended far beyond Heathrow. Airports across the UK, including Gatwick, Manchester, and Birmingham, reported experiencing widespread cancellations and delays. Passengers at these hubs faced long waits, uncertain information, and the difficult decision of whether to remain at the airport or return home. Ryanair, another major operator, confirmed that affected passengers would be notified, adding to the general sense of apprehension.

Passengers caught in the chaos shared their frustrations. Phil White from Bexhill, for instance, recounted his experience at Gatwick. His flight to Lanzarote had boarded on time but remained stuck on the tarmac for hours. "We’ve been told the radar is down and we can’t take off," Phil told BBC Your Voice, highlighting the lack of precise information reaching those directly affected. He described the pilot’s repeated announcements, explaining they were waiting for updates from air traffic control, underscoring the communication vacuum during such critical incidents. This scenario was replicated countless times across the country, with passengers trapped on planes, in departure lounges, or facing lengthy queues at check-in desks and customer service points. Many missed crucial connecting flights, business meetings, or precious holiday time, with the disruption extending into subsequent days.

British Airways, in a statement, acknowledged the severe impact, confirming it was "forced to cancel or divert more than 100 flights on Tuesday afternoon." A spokesperson added, "We’re doing everything we can to keep our customers updated and make arrangements for them to continue their journeys." The airline advised customers whose flights had been cancelled not to travel to the airport, a common plea during major disruptions to prevent further overcrowding and operational strain. They also requested patience, noting their call centres were "incredibly busy." EasyJet similarly confirmed significant cancellations and delays, reiterating the advice for passengers to check their flight status before heading to the airport.

Nats released statements throughout the day, initially confirming the technical issue and apologising for the delays. By Tuesday evening, the organisation announced that its flight systems were "starting to recover," but cautioned that the full resumption of normal operations would take time. Nats explained that engineers were "on site" and "working urgently to resume normal operations as quickly as possible." They advised passengers to check their flight status with their airline and promised updates on their website, www.nats.aero, and via their X (formerly Twitter) account.

Even with Nats’ flight processing system beginning its recovery, the repercussions of the outage were expected to persist for several days. The intricate web of global aviation means that once a system is disrupted, aircraft and crew are often left in the "wrong place." Planes might be stranded at an airport far from where they are needed for their next scheduled flight, and flight crews could exceed their legally mandated working hours, leading to further cancellations and delays. This logistical nightmare meant that even after the technical issue was resolved, the industry faced a significant challenge in repositioning aircraft and crews, effectively untangling the operational snarl created by the outage.

The incident also drew the attention of the government. Transport Secretary Heidi Alexander weighed in on the situation, acknowledging the severity of the disruption. "It will take time to fully resume flights, so continue to check with airlines," she advised passengers via X. Crucially, she added, "I am seeking assurances that lessons will be learned and systems that support aviation are up to the job." This statement underscored the need for a thorough investigation into the root cause of the technical failure and a review of the resilience of critical national infrastructure like air traffic control systems.

The incident prompted wider discussions about the robustness of the UK’s aviation infrastructure. As air travel continues to grow, the reliance on complex, interconnected digital systems becomes ever more critical. A single point of failure, as demonstrated by the Nats outage, can have disproportionately large consequences. The economic impact on airlines, airports, and the broader tourism sector, coupled with the inconvenience and stress caused to thousands of travellers, highlighted the vulnerability of modern travel networks. The coming days and weeks would likely see a detailed inquiry into what went wrong, ensuring that such a widespread failure of a fundamental system is prevented in the future, safeguarding the UK’s position as a major aviation hub.